One method to control intake and exhaust valve operation during engine operation is described in U.S. Pat. No. 6,374,813. This method presents a means to control electromagnetically actuated valves to promote cylinder air charge swirl. Valves are operated independently and control is based on operating conditions of the engine. Further, the disclosure also describes several valve configurations that may be operated in one or more operational modes.
The inventors herein have recognized that the above-mentioned method can have several disadvantages. Specifically, the approach may degrade engine breathing based on intake or exhaust manifold design or dynamics. For example, certain intake manifolds are constructed with long and short runners to improve engine breathing and performance. Operation according to prior approaches can result in degraded breathing depending on valve operation at different engine speed/load combinations and intake manifold geometry. Further, operation according to prior approaches may increase emissions in systems with asymmetric exhaust systems since all of the cylinder valves will be operated similarly.